A turbine blade is inserted into a rotor by concentrically aligning and slidably inserting a male blade root within a tightly conforming corresponding female slot in the rotor while the rotor is suspended in a fixture. Given the physical weight and length of a rotor blade, it is challenging to align corresponding blade root and rotor slot structures with sufficient precision to slide the blade into its inserted position within the rotor.
Past known insertion methods and tools have included manual blade manipulation by human operators using portable hand dollies; robotic blade manipulation arms in factory manufacturing or service facilities rather than field environments; pneumatic table blade lifts and overhead cranes or equivalent manual hoists Each of the known blade insertion methods and tools has disadvantages in manufacturing or service facilities or in field installation sites.
Manual blade manipulation by human operators with wheeled dollies and other non-supported, muscle-manipulated tools is physically exhausting to the operators, as they must physically lift the blade into vertical alignment position with the rotor while simultaneously laterally aligning the blade root and rotor slot. Unsupported manual blade lifting and vertical/lateral alignment manipulation also risks potential blade damage if the blade slips or drops due to mishandling error.
Robotic blade manipulation arms are helpful for constructing or maintaining turbine blades that are removed from a rotor, but their relatively large size and limited range of offset blade manipulation motion that otherwise might risk tipping of robotic tool due to the heavy offset blade load makes them impractical for use as a blade insertion tool.
As with robotic blade manipulation arms, air-powered table-type lifts have relatively large footprints that are more suited for blade installation in manufacturing or service sites but are often too large for practical use in turbine field sites. Vertical position of the pneumatic table changes during blade loading and unloading, which potentially shifts the table's center of gravity. Loading and unloading weight on the pneumatic table also imparts oscillatory motion on the table, making lateral blade root/rotor slot alignment difficult.
Overhead cranes and hoists require insertion of the blades at a 12 o'clock elevated radial position on the suspended rotor, rather than at a 6 o'clock ground-level position, because the suspended rotor lack of vertical clearance interferes with crane or hoist positioning from under the rotor. It is more difficult for human operators to install blades into a rotor from a 12 o'clock elevated position as compared to floor elevation installation.